<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>状态改变事件</title>
    <style>
        *{
            border:1px solid red;

        }

    </style>

</head>
<body>
<div onclick="alert('div')">
    <p onclick="alert('p')">
        <input type="button" value="按钮" onclick="alert('按钮')">
    </p>
</div>
<div id="d1" ></div>
<select onchange="changefn()" id="s1">
    <option value="bj">北京</option>
    <option>上海</option>
    <option>广州</option>

</select>

<script>
    //页面加载完成事件
    // onload = function() {
    //     d1.innerText = "啦啦啦";
    // }
    function changefn(){
        alert("值改变了"+s1.value)

    }


</script>

</body>
</html>